1. Field of the Invention
The present invention relates to a novel control system relating generally to wiper assemblies for sweeping a glass surface on a vehicle. More particularly, the invention concerns a wiper assembly which includes a feed conduit connected to a fluid pump and liquid reservoir of a vehicle with a novel control unit associated with the feed conduit for precisely controlling the flow of washing liquid to the glass surface of the vehicle.
2. Discussion of the Prior Art
Most modern motor vehicles provide a wiper assembly for wiping the windshield of the vehicle and some type of washing system for washing the windshield of the vehicle. As a general rule, a washing liquid reservoir is provided in the engine compartment of the vehicle along with a pump which pumps the washing liquid from the reservoir toward hood-mounted washer heads that deliver the washing liquid to the windshield at a location about the windshield wiper.
A common drawback of the vehicle systems which include two hood-mounted washer heads is that during the windshield washing process the cleaning fluid is delivered to the windshield either at a location above the wiper blade, which is typically partly through its upward cycle, or alternatively at a point below the wiper blade when the wiper blade is partly through its downward path. This arrangement results in the washing fluid being spread in a solid fan dispersment, temporarily impairing the driver's vision while also allowing the upward path of the wiper blade to smear the residue on the glass further impairing the view of the driver. Because of this drawback the vehicle operator is required to repeatedly supply washing fluid to the windshield in order to adequately clean the windshield and thus repeatedly impairing the vision of the driver.
A number of prior art patents disclose various types of windshield washer apparatus that can be removably attached to a conventional wiper blade. Exemplary of such an apparatus is that disclosed in U.S. Pat. No. 4,517,704 issued to Benson. This apparatus includes an elongated member defining a generally U-shaped cross section and including adjacent one side thereof a tubular portion extending the longitudinal extent of the elongated member, the tubular portion defining a plurality of apertures therein. The elongated member further includes adjacent an opposite side thereof, a U-shaped channel portion extending longitudinally of the elongated member. An elongated, hollow tubing removably retained by the U-shaped channel portion is interconnected at one end to an open end of the tubular portion and at the other end to a conduit from a cleaning solution source.
Another prior art windshield washer apparatus is disclosed in U.S. Pat. No. 4,516,288 issued to Benson. This apparatus includes apparatus that is disclosed in U.S. Pat. No. 4,517,704 issued to Fizyta. This apparatus includes a spray nozzle mounted on the wiper arm intermediate the ends of the wiper blade. The nozzle includes a first baffle surface disposed at an obtuse angle relative to a base surface and at an acute angle relative to a transverse frontal wall surface upstanding from the base surface. A fluid dispensing orifice extends through the transverse wall with its axis normal to the frontal wall surface. Secondary baffle surfaces are provided by means of a notched-out portion formed in the first baffle surface. The orifice directs a stream of fluid such that a primary spray of the fluid is dispersed to upper and intermediate bladed areas of the windshield and a secondary spray of fluid is dispersed normal to the lower bladed area of the windshield.
Still another prior art windshield washer apparatus is disclosed in U.S. Pat. No. 3,793,670 issued to Riester, et al. This apparatus includes an arm mounted spray nozzle. The nozzle includes a baffle projecting from a base member having a surface at a compound angle with respect to the member for dispersing the fluid into a conical-shaped configuration of droplets and directing the array of droplets toward the windshield in the path of the windshield wiper. Washer solvent under pressure is directed through an orifice toward the baffle. A nipple is provided at the orifice to which flexible tubing extending along the length of the arm is connected at one end. At the other end the tubing is connected to a washer pump so that washer fluid can be directed through the tubing and the orifice against the baffle.
As a general rule, the prior art vehicle windshield washing systems fail to effectively and efficiently clean the vehicle windshield without undesirable smearing and in use tend to be little better than the conventional hood-mounted washer heads typically found on most modern vehicles.
The thrust of the present invention is to overcome the drawbacks of the prior art vehicle windshield washing systems by providing a novel vehicle wiper assembly that includes not only a liquid feed conduit carried directly by the vehicle wiper system, but also uniquely includes a novel control unit that precisely regulates the flow of fluid onto the wind shield. More particularly, the control unit includes sensors that sense the position of the wiper blade and then controls the flow of washing onto the vehicle windshield based upon the position of the wiper blade. This design eliminates the dangerous driving condition of the fan water spray on the windshield obstructing the driver's view of the road. The washing liquid feed conduit extending from the combination washer tube and blade assembly is interconnected with the vehicle washing fluid reservoir via the control unit by an elongated flexible tube which can readily be connected to the washing liquid pump that is typically housed within the vehicle engine compartment.
With this novel arrangement, the wiper assembly of the present invention can be used to replace the wiper assembly supplied with the vehicle and can be interconnected with the washing liquid reservoir by simply removing the flexible tube used to connect the liquid pump with the hood-mounted spray head and replacing it with the flexible tube and combined washer tube and blade assembly unit that is interconnected with the liquid feed conduit of the vehicle. This replacement can be accomplished quickly and easily and without the necessity of making any major changes to the stock vehicle windshield washing system.
One embodiment of the invention comprises a single, pre-assembled unit containing a washer blade assembly with an extended washer tube permanently attached to, and made an integral part of, the washer blade assembly.
This unit can be placed on vehicles at the point of manufacture or retro-fitted to existing vehicles by simply detaching the existing washer blade assembly and replacing it with the combination washer tube and blade invention. Another method of accomplishing the same result as a washer tube and blade assembly is to extrude the wiper blade to include a hollow tube adapted to carry and expel the washing fluid to the surface of the windshield in the same manner as the washer tube and blade assembly unit.